Apparatus for low-pressure casting of metallic products

ABSTRACT

An apparatus for low-pressure casting of metallic products includes at least one forming die which is provided with a cavity which is adapted to receive a molten metallic mass. The forming die includes at least two parts which can move between an open configuration, in which they are mutually spaced apart, and a closed configuration, in which together they define the cavity, the forming die being supported and moved by a manipulator with multiple degrees of freedom, which has movable parts that are actuated by electric motor components driven by a control unit.

TECHNICAL FIELD

The present disclosure relates to an apparatus for low-pressure casting of metallic products.

BACKGROUND

As is known, the production of metallic alloy castings using the low-pressure casting process involves the use of forming dies that have impressions, into which is poured a metallic mass which is first melted by way of adapted smelting furnaces.

The forming dies are normally constituted by two or more parts that can be moved relative to each other, known in the sector as “half-dies”, which can pass from an open configuration, in which they are mutually spaced apart, to a closed configuration, in which they are in mutual contact so as to define the above-mentioned impressions together.

In more detail, at the start of the process the half-dies are mutually moved apart, so as to enable an operator to carry out a series of preliminary preparatory operations on the forming impressions.

Once the preparatory operations are concluded, the two half-dies are closed, to form the forming die, and are arranged at the smelting furnace which introduces the molten metal inside them.

When the casting has solidified and cooled sufficiently, the forming die is moved to an ejection area and the two half-dies are opened to allow the castings thus formed to be ejected.

In moving the half-dies, the use is known of manipulators in which the movements are actuated by a series of hydraulic actuators.

Such solution, although facilitating the movement of the half-dies, increases the safety risks for the operators and for the environment.

The possible consequences of an oil leak in a high-temperature environment like that in a foundry are to be, for example, considered.

Furthermore, such manipulators have considerable weight and encumbrances, and feature construction solutions that are complex and, therefore, have particularly high final costs.

It must likewise be considered that manipulators of the hydraulic type are generally slow, as well as being non-flexible and rather imprecise in their movements.

In fact, hydraulic actuators cannot execute rotations of upper half-dies of more than 90°, so defining only two positions for them.

SUMMARY

The present disclosure provides an apparatus for low-pressure casting of metallic products that overcomes the drawbacks of the cited known art.

Within this aim, the disclosure provides an apparatus that makes it possible to move in a precise, rapid and highly repeatable manner the parts that make up the forming die.

The disclosure also provides an apparatus that is particularly flexible, that makes it possible to simplify the layout of the entire plant in which it is inserted, and is capable of being easily adapted to any changes in the latter.

The disclosure provides an apparatus that is safe for the users and the persons working in the vicinity of the plant, and also for the environment.

The above aim and the above and other advantages, which will become better apparent hereinafter, are achieved by providing an apparatus for low-pressure casting of metallic products, which comprises at least one forming die which is provided with a cavity which is adapted to receive a molten metallic mass, said forming die comprising at least two parts which can move between an open configuration, in which said two parts are mutually spaced apart, and a closed configuration, in which said two parts together define said cavity, said forming die being supported and moved by a manipulator with multiple degrees of freedom, said apparatus being characterized in that said manipulator comprises a plurality of movable parts which are actuated by electric motor means which are driven by a control unit.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the disclosure will become better apparent from the description of a preferred, but not exclusive, embodiment of an apparatus according to the disclosure, illustrated by way of non-limiting example in the accompanying drawings wherein:

FIG. 1 is a side view of an apparatus according to the disclosure and of a smelting furnace;

FIG. 2 is a perspective view of a component of the apparatus of FIG. 1;

FIGS. 3 and 4 are perspective views of another component of the apparatus of FIG. 1;

FIGS. 5 and 6 are perspective views of a detail of the component of FIGS. 3 and 4;

FIG. 7 is a view from above of the apparatus of FIG. 1;

FIG. 8 is a cross-sectional view taken along the line VIII-VIII of FIG. 7; and

FIGS. 9a to 9d are perspective views of a component of an apparatus, according to the disclosure, in four different operating configurations.

DETAILED DESCRIPTION OF THE DRAWINGS

With reference to the figures, an apparatus for low-pressure casting of metallic products is generally designated by the reference numeral 1.

The apparatus 1 comprises a forming die 2 which is constituted by two parts 4 a, 4 b, also called “half-dies”, which can move between an open configuration, in which they are mutually spaced apart, and a closed configuration, in which they are in mutual contact.

More specifically, in the closed configuration, the two parts 4 a, 4 b together define a cavity 3 that is adapted to receive a molten metallic mass.

For example, the metallic mass can be heated and brought to the liquid or semisolid state by a smelting furnace 6, which is conventional and is not described in detail.

The two parts 4 a, 4 b of the forming die 2 are supported and moved by a manipulator 10 with multiple degrees of freedom.

According to the present disclosure, all the movements of the movable parts of the manipulator 10 are obtained with transmission means which are actuated by motor means of the electric type, driven by an adapted control unit.

More precisely, the rotating movements of the manipulator 10 are obtained with high-torque reduction gears actuated by brushless motors, while the linear movements are obtained with linear screw actuators which are also actuated by further brushless motors.

Preferably, in the manipulator 10 electric motors are used with a degree of protection at least of the order of IP65, powered with cables protected by sheaths that can withstand high temperatures.

In the example shown, the manipulator 10 has a stationary base 5 and a post 11 mounted thereon so that it can rotate about a first axis 100 which is oriented vertically.

Advantageously, in a variation of embodiment not shown in the figures, the base 5 can be hung from the ceiling and the post 11 can extend downward therefrom.

The post 11 and the stationary base 5 are mutually connected by way of a first joint 21, which is associated with a first electric motor 31 with the interposition of a first reduction gear 41.

A first articulation element 12 is mounted on the post 11 and can oscillate about a second axis 200 which is transverse to the first axis 100 and is oriented horizontally.

The first articulation element 12 is connected to the post 11 by way of a second joint 22 and is moved by a second electric motor 32 through a second reduction gear 42.

An arm 13 extends from the first articulation element 12 and is adapted to support and move the two parts 4 a, 4 b of the forming die 2.

In other embodiments, not shown in the figures, the apparatus 1 can comprise multiple arms 13, all connected to a single post 11.

In more detail, the arm 13 comprises an elbow-shaped portion 15 which is connected to the first articulation element 12 by way of a third joint 23, which enables that arm 13 to rotate about a third axis 300 which is transverse to the second axis 200.

Such rotation is controlled by a third electric motor 33 which is coupled to a third reduction gear 43.

Advantageously, the arm 13 is composed of a first segment 14 a, which is fixed along a fourth axis 400, which is substantially parallel to the third axis 300, and of a second segment 14 b, which can move along the fourth axis 400.

The segments 14 a and 14 b are mutually coupled by way of sliding means 24, for example constituted by a slider-and-guide system, which is conventional and not described in detail.

In this case, the second segment 14 b is mounted telescopically on the first segment 14 a and can slide along the fourth axis 400.

Preferably, the second segment 14 b is moved along the fourth axis 400 by way of a linear actuator 44 which is actuated by a fourth electric motor 34.

Second articulation elements 16 a, 16 b are mounted respectively on the segments 14 a, 14 b, and can oscillate about fifth axes 500 a, 500 b which are arranged transversely to the fourth axis 400.

The connection between the second articulation elements 16 a, 16 b and the segments 14 a, 14 b is obtained by way of fifth joints 25 a, 25 b which are moved by fifth reduction gears 45 a, 45 b which are associated with fifth electric motors 35 a, 35 b.

The second articulation elements 16 a, 16 b have respectively a first head 17 a and a second head 17 b, each of which can oscillate about a sixth axis, respectively 600 a and 600 b.

The sixth axes 600 a, 600 b, about which the heads 17 a, 17 b oscillate, are arranged transversely to the fifth axes 500 a, 500 b and are defined by sixth joints 26 a, 26 b which connect those heads 17 a, 17 b to the second articulation elements 16 a, 16 b.

Conveniently, sixth electric motors 36 a, 36 b are mounted on the second articulation elements 16 a, 16 b and are adapted to actuate the sixth joints 26 a, 26 b by way of sixth reduction gears 46 a, 46 b.

The heads 17 a, 17 b support respectively a first flange and a second flange 18 a, 18 b which are mounted so that they can rotate about seventh axes 700 a, 700 b which are transverse to the sixth axes 600 a, 600 b.

The parts 4 a, 4 b, of the forming die 2 can rotate independently of each other, about the seventh axis 700 a, 700 b thereof, by way of seventh brushless motors 37 a, 37 b which are connected to seventh, precision reduction gears 47 a, 47 b, ensuring the coupling between them.

The flanges 18 a, 18 b are connected to the heads 17 a, 17 b by way of seventh joints 27 a, 27 b which are associated with the seventh electric motors 37 a, 37 b with the interposition of seventh reduction gears 47 a, 47 b.

Each flange 18 a, 18 b is adapted to support one of the two parts 4 a, 4 b of the forming die 2, which therefore can be moved in an effective and precise manner using the manipulator 10 according to the disclosure.

Conveniently, the above mentioned motors 31-37 b, i.e. the respective joints 21-23 and 25 a-27 b, or the sliding means 24, are associated with transducers, for example encoders, for controlling the position of the movable parts 11-18 b of the manipulator 10.

The movements of the manipulator 10 and the handling of the forming die 2, such as for example the transition of the two parts 4 a and 4 b from the open position to the closed position, and vice versa, are managed by a control unit which is controlled by an operator.

Conveniently, such control unit has a microprocessor system which is connected to the electrical/electronic parts of the apparatus 1, and is configured to control the manipulator 10 in various different operating modes, such as for example an automatic mode and a manual mode.

With reference to FIG. 6, the head 17 a also comprises an ejector 38 which is constituted by an electric motor that enables a movement of the head 17 a along its seventh axis 700 a.

In other embodiments not shown in the figures, the ejector 38 is constituted by a hydraulic actuator.

Operation of the apparatus according to the disclosure is as follows.

In an initial step of the casting process, the two parts 4 a and 4 b of the forming die 2 are in the open configuration, i.e. they are spaced apart from each other in order to allow the operator to carry out any necessary operations in preparation of the cavity 3.

Simultaneously, in the smelting furnace 6 a metallic mass is heated until it reaches a liquid or semisolid state.

Subsequently, the two heads 17 a, 17 b of the manipulator 10 are moved mutually close together, bringing the two parts 4 a and 4 b of the forming die 2 to the closed configuration, in which they define the cavity 3 together.

By way of the manipulator 10, the forming die 2 is then positioned at the smelting furnace 6 so as to allow the introduction of the molten metallic mass into the cavity 3.

Once the metallic mass has solidified completely it is possible to open the two parts 4 a and 4 b of the forming die 2 and eject the desired casting.

In practice it has been found that the disclosure achieves the set aim and advantages, an apparatus for low-pressure casting of metallic products having been provided that makes it possible to move in a precise, rapid and highly repeatable manner the parts 4 a and 4 b that make up the forming die 2.

In fact, since the movable parts 11-18 of the manipulator 10 are actuated by electric motors 31-37, all the movements occur with high precision and repeatability, as well as very rapidly.

It should be noted that the apparatus 1 is considerably versatile in that it makes it possible to carry out various different operations and/or functions with a same motor and/or actuator via a same movement.

By way rotations of the motors 32-37 b it is in fact possible to rotate the parts 4 a and 4 b of the die 2 in different configurations as shown in FIGS. 9a to 9 d.

The use of electric motors, instead of hydraulic actuators, makes it possible to rotate the parts 4 a, 4 b, even through 360°, thus defining four positions for them.

For example, it is possible to rotate through 90° the parts 4 a and 4 b in order to bring them from a position in which they are facing each other (FIG. 9a ) to a position in which they are lowered (FIG. 9b ), for a graphitizing operation, and by continuing the movement it is possible to rotate the parts 4 a and 4 b through 180°, an operation not permitted in conventional apparatuses that use hydraulic actuators, in order to bring them to another position (FIG. 9d ), for automatic cleaning

By rotating the parts 4 a, 4 b from the graphitizing position (FIG. 9b ) through 90° about a different axis, it is possible to bring them to a fourth position (FIG. 9c ) for manual cleaning

As a consequence, the forming die 2 can be brought to different stations and positioned very easily, thus simplifying the layout of the plant where the apparatus 1 is installed, as well as simplifying any modifications to it.

In addition it should be noted that there is a considerable energy saving by using the electric motors 31-37 b.

From experimental tests it has emerged that with an apparatus according to the disclosure power consumption in the order of 3 kW is achieved, against consumption in the order of 10 kW for similar, conventional apparatuses that use hydraulic actuators.

Last but not least, it has been found that the apparatus 1 according to the disclosure is safe for the users and the persons working in the vicinity of the plant, and also for the environment.

The apparatus for low-pressure casting of metallic products according to the disclosure is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; furthermore, all the details may be substituted by technically equivalent elements.

Naturally, the materials employed, as well as the dimensions and the shapes, may be any according to requirements and to the state of the art.

The disclosures in Italian Patent Application No. 102019000007824 from which this application claims priority are incorporated herein by reference. 

1.-11. (canceled)
 12. An apparatus for low-pressure casting of metallic products comprises: at least one forming die provided with a cavity which is adapted to receive a molten metallic mass, said forming die comprising at least two parts configured to move between an open configuration, in which said two parts are mutually spaced apart, and a closed configuration, in which said two parts together define said cavity, said forming die being supported and moved by a manipulator with multiple degrees of freedom, wherein said manipulator comprises a plurality of movable parts that are actuated by electric motor means driven by a control unit.
 13. The apparatus according to claim 12, wherein said manipulator comprises a post which is mounted so that said post is configured to rotate on a stationary base, about a first axis, said post and said stationary base being mutually connected by a first joint associated with first electric motor means with the interposition of first transmission means.
 14. The apparatus according to claim 13, wherein said manipulator comprises a first articulation element mounted so that said first articulation element is configured to oscillate on said post, about a second axis which is transverse to said first axis, said first articulation element and said post being mutually connected by way of a second joint associated with second electric motor means with the interposition of second transmission means.
 15. The apparatus according to claim 14, wherein said manipulator comprises an arm mounted so that said arm is configured to rotate on said first articulation element about a third axis transverse to said second axis, said arm and said first articulation element being mutually connected by way of a third joint associated with third electric motor means with the interposition of third transmission means.
 16. The apparatus according to claim 15, wherein said arm comprises: a first segment, fixed along a fourth axis which is substantially parallel to said third axis, a second segment configured to move along said fourth axis, said first segment and said second segment being mutually connected by sliding means associated with fourth electric motor means with the interposition of fourth transmission means.
 17. The apparatus according to claim 16, wherein said arm comprises an elbow-shaped portion integral with said second segment and is connected to said first articulation element by said third joint.
 18. The apparatus according to claim 16, wherein said manipulator comprises second articulation elements mounted so that said second articulation elements are configured to oscillate on said first segment and said second segment, about fifth axes which are transverse to said fourth axis, said second articulation elements being connected to said first segment and said second segment by fifth joints respectively associated with fifth electric motor means with the interposition of fifth transmission means.
 19. The apparatus according to claim 18, wherein said manipulator comprises a first head and a second head, which are mounted so that said first and second heads are configured to oscillate on said second articulation elements, about sixth axes which are transverse to said fifth axes, said first head and said second head being connected to said second articulation elements by sixth joints respectively associated with sixth electric motor means with the interposition of sixth transmission means.
 20. The apparatus according to claim 19, wherein said manipulator comprises a first flange and a second flange mounted so that said first and second flanges are configured to rotate on said first head and said second head about seventh axes which are transverse to said sixth axes, said first flange and said second flange being connected to said first head and said second head by seventh joints respectively associated with seventh electric motor means with the interposition of seventh transmission means, said first flange and said second flange being adapted to support respectively said two parts of said die.
 21. The apparatus according to claim 20, wherein said first to seven electric motor means comprise brushless motors associated with corresponding position transducers.
 22. The apparatus for low-pressure casting of metallic products according to claim 15, comprising one or more arms and/or one or more articulation elements and/or one or more manipulators, wherein it is moved by electric motor means. 